The present invention relates to a magnetic measuring apparatus and more specifically, to a magnetic measuring apparatus appropriate for measuring magnetic fields spread in an ambient space about a head (brain), a chest (heart, stomach), an abdomen (liver), a fetus, and so on.
FIG. 33 shows a prior art (U.S. Pat. No. 5,475,306) magnetic measuring apparatus for measuring magnetic fields spread in the ambient space about a human bead.
The magnetic measuring apparatus 500 comprises a cryogenic vessel CR' composed of an inner vessel CRI' and an outer vessel CRO having a domed bottom D for accepting the human head, a lid LD' for closing an opening OP' provided in the top of the cryogenic vessel CR', a multiplicity of magnetic sensor units 50 suspended by pipes PP respectively from the lid LD' so as to be seated directly on the upper surface of the domed bottom D, signal lines 4 for transmission of output signals from their respective magnetic sensor units 50, an interface device 20 connected to the signal lines 4, a data processor device 30 for analyzing the output signals of the magnetic sensor units 50 to specify magnetic fields spread in the ambient space about the head and calculating activity data of a brain B from the magnetic fields, and a display device 40 for displaying the calculated activity data.
The space between the inner vessel CSI' and the outer vessel CRO is filled with a thermal insulating material Dn and air is evacuated therefrom.
Denoted by PA is a packing made of e.g. rubber.
A coolant feed/exhaust double tube ST is provided for feeding to and exhausting a coolant from the cryogenic vessel CR'. The coolant may be a liquid helium (4.2K).
As the prior art magnetic measuring apparatus 500 shown in FIG. 33 has the magnetic sensor units 50 mounted in a suspended arrangement, the opening OP' is formed substantially equal in size to the cross section of a human head.
But when the opening OP' is considerably large (over 10 cm in diameter), it causes a problem of passing of much heat thus increasing the evaporation loss of the coolant and the cost of running.
In addition, there is another problem that the cryogenic vessel CR' cannot have an overhand reducing the opening OP' because the magnetic sensor units 50 are vertically suspended from the lid LD'.
Furthermore, there is the other problem that the domed bottom D of the magnetic measuring apparatus 500 accepts the head of one single test object at a time, thus throughput cannot be increased.